Impact of Substrate Glycoside Linkage and Elemental Sulfur on Bioenergetics of and Hydrogen Production by the Hyperthermophilic Archaeon Pyrococcus furiosus

• Published in: Applied and Environmental Microbiology Vol. 73; no. 21; pp. 6842 - 6853
• Main Authors: Chou, Chung-Jung, Shockley, Keith R, Conners, Shannon B, Lewis, Derrick L, Comfort, Donald A, Adams, Michael W.W, Kelly, Robert M
• Format: Journal Article
• Language: English
• Published: Washington, DC American Society for Microbiology 01.11.2007; American Society for Microbiology (ASM)
• Subjects: Archaea; Bioenergetics; Biological and medical sciences; Biotechnology; Cell culture; Chemical Phenomena; Chemistry; Fundamental and applied biological sciences. Psychology; Gene Expression Regulation, Archaeal; Genes; Genome, Archaeal; Glycosides - metabolism; Hot Temperature; Hydrogen; Hydrogen - metabolism; Microbiology; Microorganisms; Molecules; Oligonucleotide Array Sequence Analysis; Open Reading Frames; Physiology and Biotechnology; Protein folding; Pyrococcus furiosus; Pyrococcus furiosus - enzymology; Pyrococcus furiosus - genetics; Pyrococcus furiosus - physiology; Sulfur - metabolism; Archaeobacteria; Hydrogen; Hyperthermophily; Production; Pyrococcus furiosus; Bacteria; Biofuel; Glycoside; Sulfur
• ISSN: 0099-2240; 1098-5336
• DOI: 10.1128/AEM.00597-07

Glycoside linkage (cellobiose versus maltose) dramatically influenced bioenergetics to different extents and by different mechanisms in the hyperthermophilic archaeon Pyrococcus furiosus when it was grown in continuous culture at a dilution rate of 0.45 h⁻¹ at 90°C. In the absence of S⁰, cellobiose-grown cells generated twice as much protein and had 50%-higher specific H₂ generation rates than maltose-grown cultures. Addition of S⁰ to maltose-grown cultures boosted cell protein production fourfold and shifted gas production completely from H₂ to H₂S. In contrast, the presence of S⁰ in cellobiose-grown cells caused only a 1.3-fold increase in protein production and an incomplete shift from H₂ to H₂S production, with 2.5 times more H₂ than H₂S formed. Transcriptional response analysis revealed that many genes and operons known to be involved in α- or β-glucan uptake and processing were up-regulated in an S⁰-independent manner. Most differentially transcribed open reading frames (ORFs) responding to S⁰ in cellobiose-grown cells also responded to S⁰ in maltose-grown cells; these ORFs included ORFs encoding a membrane-bound oxidoreductase complex (MBX) and two hypothetical proteins (PF2025 and PF2026). However, additional genes (242 genes; 108 genes were up-regulated and 134 genes were down-regulated) were differentially transcribed when S⁰ was present in the medium of maltose-grown cells, indicating that there were different cellular responses to the two sugars. These results indicate that carbohydrate characteristics (e.g., glycoside linkage) have a major impact on S⁰ metabolism and hydrogen production in P. furiosus. Furthermore, such issues need to be considered in designing and implementing metabolic strategies for production of biofuel by fermentative anaerobes.